Add HYPRE.Init()

This patch adds the function `HYPRE.Init()` which i) calls `MPI.Init`
(unless MPI is already initialized), ii) calls `HYPRE_Init`, and iii)
adds a Julia exit hook which calls `HYPRE_Finalize` (if the keyword
argument `finalize_atexit` is `true`).

src/HYPRE.jl

@@ -19,6 +19,29 @@ using .LibHYPRE: @check
 # Internal namespace to hide utility functions
 include("Internals.jl")
 
+
+"""
+    Init(; finalize_atexit=true)
+
+Wrapper around `HYPRE_Init`. If `finalize_atexit` is `true` a Julia exit hook is added,
+which calls `HYPRE_Finalize`. This method will also call MPI.Init unless MPI is already
+initialized.
+"""
+function Init(; finalize_atexit=true)
+    if !(MPI.Initialized())
+        MPI.Init()
+    end
+    # TODO: Check if already initialized?
+    HYPRE_Init()
+    if finalize_atexit
+        # TODO: MPI only calls the finalizer if not exiting due to a Julia exeption. Does
+        #       the same reasoning apply here?
+        atexit(HYPRE_Finalize)
+    end
+    return nothing
+end
+
+
 ###############
 # HYPREMatrix #
 ###############

test/runtests.jl

@@ -10,8 +10,8 @@ using SparseArrays
 using SparseMatricesCSR
 using Test
 
-MPI.Init()
-HYPRE_Init()
+# Init HYPRE and MPI
+HYPRE.Init()
 
 @testset "HYPREMatrix" begin
     H = HYPREMatrix(MPI.COMM_WORLD, 1, 5)